I need advice w my MIL😭

So a couple months ago I posted about my MIL and how me and my SO decided our baby won’t be allowed around her and her bf unless we are around (I will post the post below) but now I’m having issues with an upcoming 4D ultrasound. I have a 30 week ultrasound coming up on Saturday and I invited my MIL and she asked if she could bring her daughter and I told her I would think about it since I’m not allowing my sister to go and she said “it’s okay I’ll just have her wait in the car” like okay so what’s the point of her coming then? Anyways she then went on to say she’s going to bring her boyfriend and GIRLS I’m NOT comfortable with him coming. I was not raised around men I was raised by two lesbians who are my grandmas so having a man there in general is just super uncomfortable and not my thing. Not to mention he’s crazy and honestly has no business going he’s my SO UNCLE (I know, confusing) but if I’m not inviting my SO dad then why should his uncle come? He’s freaking nuts he told her 9 year old daughter on Friday he was going to kill my MIL like this man is just not someone I want there or around my son period. I don’t know how to tell her how I feel, usually I’m a very upfront and blunt person but she is so sensitive and turns everything into something it’s not but I’m now stressing about it. It’s not her place to even invite people you know? Someone please just give me a way to tell her I only want her to come in a way that she wouldn’t freak out. I hate stressing about things. I feel I should not even have to stress about something like this but she wants to invite everyone and their damn dog I just don’t know what to do😭 she doesn’t take hints very easily she literally needs to be told how it is straight up but also in a way to where she won’t act crazy I didn’t invite her to my first ultrasound and she freaked out she was crying and asking if she’d ever be able to see the baby and made it about herself which is why I’m having a hard time telling her.

My last post about her:

So it’s been a topic for me and my SO about how we will address certain issues involving our son and his mom and step dad. Every time and I’m not kidding, EVERY TIME me and my SO decide to stop by his moms house to see her and his siblings his mom and her boyfriend are always fighting. He chases her up the stairs, threatens her etc in front of all of the kids (ages 9-14). I just feel like this isn’t a safe environment for my son. I don’t want him growing up around violence. Me and my SO have both decided our son won’t be able to go around without us being there. Are we wrong for this decision? We haven’t had a talk with her yet about it but I know when we do she’ll freak! I just want to be prepared for this upcoming war.